business of bottoms. Where's George? Wanted no part of this, nowhere to be seen. Over here. He's working over there. Stars from j.lo to Kim ca Kardashian are making a big behind fashionable. You can have mine. I have never understood this as someone trying to get rid of my behind. So I had to get to the bottom of this asset enhancement. There was a time when big butts weren't, shall we say, in vogue. I can't believe it's so round. It's like out there. Gross. Reporter: Even if sir mix-a-lot professed to loving them. ? I like big butts and I cannot lie ? today, a big booty is where it's at. Kim Kardashian, j.lo and azalea sing about theirs. And Nicki Minaj. ? My anaconda don't want one ? too much fanny for TV. Why is it so big right now? It's the celebrities. They have a lot of power on women's body image. Reporter: The business of the big booty is moving into high gear. Achieving it doesn't come easy. Punch gym offers the class laugh your ass off. Designed designed to sculpt the pos tear moms. See them all. Five years ago, I never made a butt bigger. Everyone wanted -- Reporter: If the permanent isn't your thing, you can slide it on. Sales of booty pop panties are up 47% compared to last year. Put my butt on. Nice and soft. One wasn't enough. Going with two. No kidding, they really work. Boom, boom. Now let's see if anyone notices ? I like big butts ? a big booty even I can enjoy for a day. Who can get enough of sir mix-a-lot. It might be my life's anthem. Sara Haines knows every word to the song. I do. You'll see that I've got -- these are the booty pop panties. Feel them. I have two pairs in. One wasn't popping enough, if you know what I mean. This is for bike riding. Very comfortable. That's not what they're thinking with this, Amy. This is for a night out, or you can ride a bike with. You have two pairs on? I have two pairs on. This is awe natural. I really am embracing it now. That was my nickname in college was bubble butt. Which came in handy on the basketball court. When you have legs like yours, I would embrace that curve. I know George and -- I just to want thank Sara for cutting me out of that piece. She surprised me in the elevator yesterday, and I was struck speechless. It was a bit of an ambush. That's why you like guys that like big butts, they cannot lie. Thanks, guys. And daymond John here from

This transcript has been automatically generated and may not be 100% accurate.

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